It is widely recognized that coating compositions based on fluorocarbon polymers, especially polytetrafluoroethylene (PTFE), serve the useful purpose of providing a nonstick surface on various articles. The cookware industry in particular has found the use of fluoropolymer finishes to be advantageous.
While cookware bearing such finishes is generally quite durable, manufacturers of nonstick cookware continue to try to improve coating compositions so that the ultimate user can have a product of superior characteristics which will last as long as possible. The same goal exists with respect to nonstick-coated articles other than cookware.
There are many patents relating to articles coated with a fluoropolymer composition of enhanced durability. Representative of some of the more recent in U.S. Pat. No. 4,180,609 issued to Vassiliou Dec. 25, 1979, directed to an article multicoated with a fluoropolymer composition which contains mica particles, mica particles coated with pigment, or metal flake in varying proportions in the different coats.
Of particular importance to the present invention in U.S. Patent application Ser. No. 956,349 filed Oct. 31, 1978 now U.S. Pat. No. 4,252,859 by Concannon and Vary, directed toward a coating composition containing a blend of PTFE and copolymers of perfluorinated polyvinyl ether and tetrafluoroethylene (TFE). This coating composition exhibited reduced crystallinity and a longer useful life than would be expected from averaging the properties of the unblended resins themselves.